Add extra_user_data option (#6)

Author: int128

README.md

@@ -102,6 +102,7 @@ This is an open source software. Feel free to open issues and pull requests.
 
 | Name | Description | Type | Default | Required |
 |------|-------------|:----:|:-----:|:-----:|
+| extra\_user\_data | Extra script to run in the NAT instance | string | `""` | no |
 | image\_id | AMI of the NAT instance. Default to the latest Amazon Linux 2 | string | `""` | no |
 | instance\_types | Candidates of spot instance type for the NAT instance. This is used in the mixed instances policy | list | `[ "t3.nano", "t3a.nano" ]` | no |
 | key\_name | Name of the key pair for the NAT instance. You can set this to assign the key pair to the NAT instance | string | `""` | no |
@@ -118,6 +119,7 @@ This is an open source software. Feel free to open issues and pull requests.
 | eip\_id | ID of the Elastic IP |
 | eip\_public\_ip | Public IP of the Elastic IP for the NAT instance |
 | eni\_id | ID of the ENI for the NAT instance |
+| eni\_private\_ip | Private IP of the ENI for the NAT instance |
 | iam\_role\_name | Name of the IAM role for the NAT instance |
 | sg\_id | ID of the security group of the NAT instance |
 

data/init.sh

@@ -18,3 +18,6 @@ iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE
 
 # Switch the default route to eth1
 ip route del default dev eth0
+
+# Run the extra script if set
+${extra_user_data}

main.tf

@@ -92,7 +92,8 @@ resource "aws_launch_template" "this" {
 
   user_data = base64encode(
     templatefile("${path.module}/data/init.sh", {
-      eni_id = aws_network_interface.this.id
+      eni_id          = aws_network_interface.this.id
+      extra_user_data = var.extra_user_data
     })
   )
 

outputs.tf

@@ -13,6 +13,12 @@ output "eni_id" {
   value       = "${aws_network_interface.this.id}"
 }
 
+output "eni_private_ip" {
+  description = "Private IP of the ENI for the NAT instance"
+  # workaround of https://github.com/terraform-providers/terraform-provider-aws/issues/7522
+  value = "${tolist(aws_network_interface.this.private_ips)[0]}"
+}
+
 output "sg_id" {
   description = "ID of the security group of the NAT instance"
   value       = "${aws_security_group.this.id}"

variables.tf

@@ -19,6 +19,11 @@ variable "private_route_table_ids" {
   default     = []
 }
 
+variable "extra_user_data" {
+  description = "Extra script to run in the NAT instance"
+  default     = ""
+}
+
 variable "image_id" {
   description = "AMI of the NAT instance. Default to the latest Amazon Linux 2"
   default     = ""